Stone says never has attention to the environment been more necessary, but he says the opportunity for an informed national debate on Canada's response to global warming is slipping away.

Group stresses seriousness of climate issue

The letter, signed by a who's who of Canada's top climate experts, says "it seems people have simply no idea how serious this issue is" even though it's clear the public accepts that global warming is a threat.

"Global warming is a problem that must be dealt with now, before it's too late," says the letter. "Any further delay will only increase the risks of damage and costs of action.

"The world needs to start down a path of greenhouse-gas reduction to avert the most serious consequences of global warming."

Even if atmospheric greenhouse gases are stabilized at current levels, it says, the Arctic would still go ice free in the summer, between 10 and 25 per cent of the world's species would still be committed to extinction, and weather will continue to become more extreme.

Many of the letter's signatories are research scientists who depend on federal granting agencies for the bulk of their funding.

But David Schindler, who won Canada's top science prize in 2001, says the scientists are confident that granting agencies will continue to support good science on its merits and on the basis of professional peer review rather than politics.

"Regardless, this is not a moment for any Canadian to be timid," Schindler said. "This is an urgent issue and I am proud to side with so many scientists who are willing to stand up for what they believe in."